Thromb Haemost 2012; 107(03): 468-476
DOI: 10.1160/TH11-07-0457
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Platelet-mediated proteolytic down regulation of the anticoagulant activity of protein S in individuals with haematological malignancies

Ilze Dienava-Verdoold
1   Department of Plasma Proteins, Sanquin Research, Amsterdam, The Netherlands
,
Marina R. Marchetti
2   Immunohematology and Transfusion Medicine Department, Ospedali Riuniti di Bergamo, Bergamo, Italy
,
Liane C. J. te Boome
3   Department of Hematology, Academical Medical Center, University of Amsterdam, Amsterdam, The Netherlands
4   Present address: Department of Hematology, Academic Medical Center, University of Utrecht, Utrecht, The Netherlands
,
Laura Russo
2   Immunohematology and Transfusion Medicine Department, Ospedali Riuniti di Bergamo, Bergamo, Italy
,
Anna Falanga
2   Immunohematology and Transfusion Medicine Department, Ospedali Riuniti di Bergamo, Bergamo, Italy
,
Harry R Koene
3   Department of Hematology, Academical Medical Center, University of Amsterdam, Amsterdam, The Netherlands
5   Pressent address: Department of Internal Medicine, St. Antonius Hospital, Nieuwegein, The Netherlands
,
Koen Mertens
1   Department of Plasma Proteins, Sanquin Research, Amsterdam, The Netherlands
6   Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
,
Herm Jan M. Brinkman
1   Department of Plasma Proteins, Sanquin Research, Amsterdam, The Netherlands
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Publikationsverlauf

Received: 06. Juli 2011

Accepted after major revision: 08. Februar 2011

Publikationsdatum:
22. November 2017 (online)

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Summary

The natural anticoagulant protein S contains a so-called thrombin-sensitive region (TSR), which is susceptible to proteolytic cleavage. We have previously shown that a platelet-associated protease is able to cleave protein S under physiological plasma conditions in vitro. The aim of the present study was to investigate the relation between platelet-associated protein S cleaving activity and in vivo protein S cleavage, and to evaluate the impact of in vivo protein S cleavage on its anticoagulant activity. Protein S cleavage in healthy subjects and in thrombocytopenic and thrombocythaemic patients was evaluated by immunological techniques. Concentration of cleaved and intact protein S was correlated to levels of activated protein C (APC)-dependent and APC-independent protein S anticoagulant activity. In plasma from healthy volunteers 25% of protein S is cleaved in the TSR. While in plasma there was a clear positive correlation between levels of intact protein S and both APC-dependent and APC-independent protein S anticoagulant activities, these correlations were absent for cleaved protein S. Protein S cleavage was significantly increased in patients with essential thrombocythaemia (ET) and significantly reduced in patients with chemotherapy-induced thrombocytopenia. In ET patients on cytoreductive therapy, both platelet count and protein S cleavage returned to normal values. Accordingly, platelet transfusion restored cleavage of protein S to normal values in patients with chemotherapy-induced thrombocytopenia. In conclusion, proteases from platelets seem to contribute to the presence of cleaved protein S in the circulation and may enhance the coagulation response in vivo by down regulating the anticoagulant activity of protein S.